1. Field of the Invention
This invention relates to valve structures and in particular to means for effectively locking a threaded valve portion to a complementary valve portion.
2. Description of the Prior Art
In one conventional form of valve, a bonnet is threadedly installed on a body portion of the valve and adjustably carries a valve stem provided at its inner end with a movable valve member adapted to have selective seating engagement with a valve seat in the body. The valve seat opens to a valve chamber. One port of the valve may open to the valve chamber and another port may open through the valve seat to the chamber so that the movable valve member effectively defines means for controlling fluid flow through the valve between the ports.
It is desirable to prevent further threaded rotation between the valve portions when they are threaded to the desired assembled relationship. It has been conventional to provide some form of locking pin installed in one portion of the valve so as to have interference with the relatively rotatable second portion, thereby preventing such undesirable further threaded rotation. A substantial number of different forms of locking pin arrangements have been developed, such as for locking nuts or bolts against rotation relative to the complementary element. Thus, illustratively, Andrew J. Gunn shows, in U.S. Pat. No. 405,773, a nut lock wherein a pin is received in a notch in one edge of a locking plate associated with the nut.
In U.S. Pat. No. 875,919, George F. Robertson shows a nut lock which is defined by an angled end portion of a link member having a turned portion so as to engage the nut in a recess within the member to which the link is pivotally connected.
Floyd W. Newman, in U.S. Pat. No. 861,139, shows a nut lock wherein the relatively rotatable elements are provided with longitudinal slots receiving a turned member which is snapped into one of the recesses to complete the locking. The locking element comprises a section of resilient wire to provide the desired snapping action.
Frederick J. Brown, in U.S. Pat. No. 930,148, shows another form of nut lock wherein a pin is extended through a hole in a flange portion of the nut with an inner end of the pin received in a hole in the mounting member.
In U.S. Pat. No. 1,470,386, Henry Miller shows a screw lock comprising a pin having oppositely turned ends carried by the slot of a fillister head screw with the ends being received in an outer recess so as to engage the walls of the mounting member in the recess. The arrangement causes the tips of the turned ends to bite into the sidewalls of the recess so as to resist reverse rotation of the screw while permitting further forward rotation.
James H. C. Boyd, in U.S. Pat. No. 1,799,950, shows a locking member having a flange provided with a plurality of radially outwardly opening notches adapted to receive the head of a locking screw spaced outwardly of the mounting member.
Arthur E. Jackman, Jr. shows, in U.S. Pat. No. 2,203,219, a cap bolt lock wherein a locking pin is driven into the mounting member in an undercut groove of a counterbore thereof to register with a peripheral groove of the screw head with a portion of the pin flowing into an annular groove in the screw head to prevent endwise movement of the screw head.
In U.S. Pat. No. 2,428,341 of Louis W. Schaaff, a locking means is shown to comprise a ring-type friction lock for securing parts against relative rotation wherein enlarged ends of the ring cause a spreading of the ring into tighter frictional engagement with the recess wall as a result of an attempted turning of the screw relative to the mounting member.
Einar Medal, in U.S. Pat. No. 3,295,579, shows a lock bolt wherein a pin is extended through mating holes in the head of the bolt and the mounting member.
Leslie Parkin, in U.S. Pat. No. 3,451,455, shows a fastener for anchoring a nut formed of a hollow body having sidewalls provided with integral resilient tongues displaced laterally by the nut as it is drawn axially into the body so that the pointed ends of the tongues are driven into the sides of the recess in which the hollow body is mounted.